Progesterone appears to be the best method of providing luteal phase support, with a relatively higher
live birth rate than placebo, and a lower risk of
ovarian hyperstimulation syndrome (OHSS) than
hCG.[1] Addition of other substances such as estrogen or hCG does not seem to improve outcomes.[1]
There is no evidence of any
route of administration of progesterone or progestins being more beneficial than others for luteal support.[1] The main ones are:
Oral administration of progesterone or progestin pills. Oral administration of progestins provides at least similar
live birth rate than vaginal progesterone capsules when used for luteal support in
embryo transfer, with no evidence of increased risk of
miscarriage.[4][8]
Intramuscular administration. Daily intramuscular injections of progesterone-in-oil (PIO) have been the standard route of administration,[6] but are not FDA-approved for use in pregnancy.
Time of initiation
The time for beginning luteal support can be put in relation to various events:
In
IVF, generally somewhere between the evening of
oocyte retrieval and day 3 after oocyte retrieval, with weak evidence indicating that 2 days after oocyte retrieval may be optimal.[10]
In
artificial insemination, luteal support is generally started on the day of insemination, or 1 to 2 days after.[11]
Duration
Luteal support given for a shorter duration than 7 weeks results in an increased risk of miscarriage in women with a dysfunctional
corpus luteum (as can be diagnosed by
blood tests for endogenous progesterone).[12] In general, however, luteal support can safely be discontinued at the time of a positive
pregnancy test (approximately 2 weeks after fertilization).[7]